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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Péče o dýchací cesty u hospitalizovaných na JIP očima samotných pacientů / The care of the airways in the patients hospitalized at the unit care in view of patients

Klozová, Ivana January 2016 (has links)
Introduction:The management of patients with a tracheostomy tube is still current. It brings stress situation not only for the patients but also staff who care for them. This issue occurs across all disciplines. The aim of this study was to determine how they feel patients at the care of the tracheotomy while hospitalization of the intensive care unit. Methodology: The research was carried out during 2015 and 2016 at the surgical intensive care unit. The group of respondents consisted of patients with established tracheostomy tube. 80 pieces were distributed questionnaires, 73 patients responded return reached 91.25%. Results: The investigation showed that the comprehensive care of a tracheostomy for patients burdensome and unpleasant. Everyone clearly stated as the most annoying and most exhausting bother them forced to cough. 90,41% of patients reported that their aspiration meets at regular intervals to be able to prepare this fact. All of the respondents perform respiratory physiotherapy and 67.12% felt that they benefit. 95.89% of respondents suffer from a sense of social isolation. 82.19% would welcome the presence of a psychologist at the ICU. Group 80.82% think that it is adequately cared about their tracheostomy during hospitalization and all have the possibility of alternative communication.
122

Étude de l'organisation à l'état solide et de la dynamique des chaines polymères dans les nanocomposites polyéthylène/POSS / Investigation of solid-state organization and polymer chain mobility in polyethylene-POSS nanocomposites

Pitard, Domitille 17 January 2008 (has links)
Liées de façon covalente à des chaînes polymères, les nanoparticules POSS (polysilses-quioxanes polyédriques) permettent l’obtention de matériaux nanocomposites hybrides orga-nique/inorganique. Ces nanoparticules présentent deux intérêts majeurs: des dimensions bien définies (cœur inorganique: 0.5 nm), ainsi que leur caractère hybride ( groupements organiques entourant les cages inorganiques). Les nanocomposites polymère/POSS peuvent présenter un renfort important des propriétés mécaniques et de la stabilité thermique de la matrice polymère. Cependant, l’origine moléculaire de ce renfort reste mal comprise. Aussi, afin de mieux comprendre le renfort des propriétés mécaniques de la matrice, nous avons étudié l’effet des particules POSS sur l’organisation à l’état solide et la dynamique des chaînes po-lymères au sein d’une matrice semi-cristalline. Pour cela, nous avons considéré une série de copolymères polyéthylène-POSS, caractérisés par une large gamme de concentration en POSS. Le polyéthylène et le POSS ayant intrinsèquement tendance à cristalliser, les copolymères présentent des organisations à l’état solide complexes que nous avons caractérisés par l’utilisation combinée de la calorimétrie différentielle à balayage (DSC), de la diffraction des rayons X aux grands angles (DRX) et de la résonance magnétique nucléaire en phase solide (RMN). Dans un second volet de cette étude, nous nous sommes intéressés à la dynamique des chaînes de polyéthylène en phase amorphe et à l’évolution de celle-ci avec le taux de charge des nanocomposites. Enfin, nous avons également étudié, de façon sélective, la dynamique des segments de chaînes de polyéthylène situés au voisinage de la charge / Grafting polyhedral oligomeric silsesquioxanes (POSS) to polymer chains offers a novel avenue to prepare hybrid organic/inorganic nanocomposites. The great advantage of such an approach holds in the very well-defined dimensions of the filler particles(inorganic core: 0.5 nm), in contrast with polymer/clay systems. Polymer/POSS nanocomposites display attractive properties such as significant mechanical reinforcement and increased thermal stability. However, the molecular origins of these enhancements are still an open question. The aim of this work is to describe both bulk organization and molecular motions of the polymer chains within these materials: these molecular properties should lead to a deeper knowledge of the enhancement of the polymer-POSS mechanical properties. The systems investigated are polyethylene (PE)-POSS copolymers with various POSS contents. The (semi-)crystalline behaviour of both PE and POSS particles induces complex bulk organization of these hybrid materials. The combined use of NMR, DSC and X-ray scattering experiments enabled to monitor the variation of the solid-state organization with the filler loading. In the second part of this work, the PE chain dynamics was investigated in the amorphous phase and its variation with the filler content was considered. Lastly, selective NMR experiments were used to probe the PE chain segment mobility close to the POSS nanoparticles
123

Numerical simulation of acoustic propagation in a turbulent channel flow with an acoustic liner / Simulation numérique de la propagation acoustique en canal turbulent avec traitement acoustique

Sebastian, Robin 26 November 2018 (has links)
Les matériaux absorbants acoustiques, qui sont d’un intérêt stratégique en aéronautique pour la diminution passive du bruit des réacteurs d’avion, conduisent à une physique complexe où l’écoulement turbulent, des ondes acoustiques, et l’absorbant interagissent. Cette thèse porte sur la simulation de cette interaction dans le problème modèle d’un écoulement de canal turbulent avec des parois impédantes, par le biais de simulations numériques aux grandes échelles implicites, dans un contexte de calcul haute performance.Une étude est d’abord faite des grandes échelles dans un canal turbulent avec des parois rigides, en s’intéressant plus particulièrement à l’effet d’une faible compressibilité (Mach <3) sur les caractéristiques de ces échelles.Un canal turbulent avec une paroi de type impédance est ensuite simulé, avec une condition habituelle de périodicité dans le sens de l’écoulement. On observe que pour des faibles valeurs de la résistance et des fréquences de résonance basses, l’écoulement est instable, ce qui engendre une onde le long de l’absorbant, qui modifie la turbulence et augmente la trainée.Enfin, on se tourne vers une simulation de canal spatial en levant la condition de périodicité dans la direction de l’écoulement, ce qui permet d’introduire une onde acoustique en entrée de domaine. L’atténuation de l’onde dans l’écoulement turbulent est étudiée avec des parois rigides, puis un absorbant acoustique est introduit. Dans cette configuration plus réaliste, il est confirmé que l’écoulement peut devenir instable au bord amont de l’absorbant, ce qui empêche l’atténuation de l’onde acoustique incidente. / Acoustic liners are a key technology in aeronautics for the passive reduction of the noise generated by aircraft engines. They are employed in a complex flow scenario in which the acoustic waves, the turbulent flow, and the acoustic liner are interacting.During this thesis, in a context of high performance computing, a compressible Navier-Stokes solver has been developed to perform implicit large eddy simulations of a model problem of this interaction: a turbulent plane channel flow with one wall modeled as an impedance condition.As a preliminary step the wall-turbulence in rigid channel flows and associated large-scale motions are investigated. A straightforward algorithm to detect these flow features is developed and the effect of compressibility on the flow structures and their contribution to the drag are studied. Then, the interaction between the acoustic liner and turbulent flow is investigated assuming periodicity in the streamwise direction. It is shown that low resistance and low resonance frequency tend to trigger flow instability, which modifies the conventional wall-turbulence and also results in drag increase.Finally, the simulation of a spatial channel flow was addressed. In this case no periodicity is assumed and an acoustic wave can be injected at the inlet of the domain. The effect of turbulence on sound attenuation is studied without liner, before a liner is introduced on a part of the channel bottom wall. In this more realistic case, it is confirmed that low resistance acoustic liners trigger an instability at the leading edge of the liner, resulting in drag increase and excess noise generation.
124

Propriedades recursivas em sistemas semidinâmicos impulsivos / Recursive properties in impulsive semidynamical systems

Jiménez, Manuel Francisco Zuloeta 06 December 2013 (has links)
A teoria de sistemas semidinâmicos impulsivos é um capítulo importante e moderno da teoria de sistemas dinâmicos topológicos. Sistemas impulsivos descrevem processos de evolução que sofrem variações de estado de curta duração e que podem ser consideradas instantâneas. Os sistemas impulsivos admitem vários fenômenos interessantes às vezes, por causa da sua irregularidade, e às vezes por causa da sua regularidade. Para muitos fenômenos naturais, os modelos determinísticos mais realistas são frequentemente descritos por sistemas que envolvem impulsos. Esta teoria vem sendo desenvolvida continuamente. O presente trabalho apresenta resultados originais sobre a teoria de conjuntos minimais, movimentos recorrentes, movimentos quase periódicos e fracamente quase periódicos, teoria de estabilidade de Lyapunov, teoria da quase estabilidade de Zhukovskij e, finalmente, a construção de trajetórias negativas para sistemas semidinâmicos com impulsos. Os resultados novos apresentados neste trabalho estão contidos em três artigos, dos quais dois já foram aceitos para publicação. Veja [13], [14] e [15] / The theory of impulsive semidynamical systems is an important and modern chapter of the theory of topological dynamical systems. Impulsive systems describe the evolution of process whose continuous dynamics are interrupted by abrupt changes of state. This kind of systems admits various interesting phenomena sometimes, because of their irregularity, and sometimes because of their regularity. In many natural phenomena, the real deterministic models are often described by systems which involve impulses. This theory has been developed continuously. This work presents original results involving the theory of minimal sets, recurrent motions, almost periodic and weakly almost periodic motions, the study of Lyapunov stability and Zhukovshij Quasi stability and the construction of negative trajectories for impulsive semidynamical systems. The new results presented in this work are contained in three papers namely [13], [14] and [15]
125

A Study On Inelastic Response Of Multi-Storey Buildings To Near-field Ground Motions

Srinivas, Bharatha 12 1900 (has links)
With the advancement in knowledge of inelastic response of structures, the design and construction practices of reinforced concrete buildings have been changing worldwide. Most of the codes are incorporating the near-fault factors and performance based designs in the seismic codes. However, further investigation is needed to identify the physical behaviour of multi-storey buildings to near-fault ground motions. At present, quantitative evaluation of response and its mitigation to near field ground motions is a popular topic in earthquake engineering field. The present study discusses the inelastic response of symmetric and asymmetric multi-storey buildings to near-fault ground motions. The possibility of design approach is based on ‘expendable top storey’ for the multi-storey RC- buildings to near field records. If such behaviour is feasible one can conceive of a structure whose top storey is permitted and designed to undergo large inelastic deformations while reducing damage in the lower storey. The concept was first proposed in an earlier research (RaghuPrasad, 1977). Such a concept juxtaposes the often-mentioned ‘soft first storey’ concept. Further in this report, the performance evaluation of multi-storey buildings near Chiplun fault in Mumbai, India is also discussed. The thesis is organized in the following chapters: Introduction in Chapter-1 contains detailed literature review on inelastic response of symmetric and asymmetric buildings, response of buildings to near-fault records, elastic and inelastic vibration absorber concepts and performance based designs. The literature reveals that considerable amount of research has been carried out on the elastic, inelastic response of structures and vibration absorber concepts to ordinary ground motions. Recently, the effect of near field ground motions on the response of multi-storey buildings is gaining much importance. Most of the research publications are available on response of symmetric buildings subjected to near field ground motions. But many problems are yet to be investigated. They are, identification of important ground motion parameters in near fault records, vibration absorber concepts and torsional response of structures subjected to pulse type ground motions. These problems are clearly mentioned in the recently published state-of-the-art review by Shuang and Li-Li (2007). In this report an attempt has been made to solve these problems. Effect of near-fault ground motions on symmetric multi-storey buildings in Chapter-2, describes simplified non-dimensionalized equations of motion to study the response behaviour of multi-storey buildings to near fault records. The non-dimensionalized equations of motion are expressed in terms of near fault ground motion parameters. The objective is to find a relation between ductility demand and near field ground motion parameters through neural network approach. For this a neural network modeling was done to predict the ductility demand in terms of peak ground acceleration, peak ground velocity, epicentral distance and pulse period of the near field ground motion. A thorough sensitive analysis is carried out, to ascertain which parameters are having maximum influence on ductility demand. In this chapter further, a comparative study is made on the inelastic seismic response of multi-storey buildings to pulse type and non pulse type ground motions. The study shows that, it is necessary to consider the effect of near fault ground motions separately and make provisions for the design in the codes of practice accordingly. Vibration absorber effect in multi-storey buildings in chapter-3, discusses the behaviour of top storey as a vibration absorber during near field ground motions. For this purpose, a five storey symmetric building model is considered as an example problem to demonstrate the effectiveness of the proposed concept. Response of the structure is obtained for the various combinations of absorber storey parameters such as mass ratio, frequency ratio and yield displacement ratio. Here mass ratio means mass of the absorber storey to that of the bottom storey and similarly for the frequency and yield displacement ratios. Observing the storey-wise variation of these responses, we can say that for a range of mass ratios, frequency ratios and yield displacement ratios, the inelastic response of top storey is large compared to the lower storeys. This range is termed as ‘effective range’. Further, in this range the top storey absorbs the vibration energy of the structure by keeping the lower storeys in elastic state i.e. acts as a vibration absorber. The top storey can also be termed as ‘expendable top storey’. Effect of near-fault ground motions on asymmetric multi-storey buildings in Chapter-4, discusses the inelastic response of asymmetric buildings to single horizontal component and two horizontal components of near fault ground motions viz., fault normal and fault parallel components. For numerical investigations eight building models are considered. Eccentricity has been created by keeping the stiffness and mass centre separately. The building models are subjected to strong motion records of Imperial Valley Array-5 (1979) and Northridge-Sylmar (1994). A detailed study on the effect of base shear strength, eccentricity and pulse period of near fault ground motions on the response is investigated. Performance of multi-Storey buildings in Chapter-5, reported a detailed procedure for the performance evaluation of structures. The procedure is applied to find the performance evaluation of multi-storeyed buildings located in near fault region. Chiplun fault in Mumbai, India has been chosen for the study because several features of that fault are clearly published (RaghuKanth and Iyengar, 2006). Results of performance evaluation of five and ten storeyed symmetric buildings with and without infill panels are studied. Ground motion records consistent with the hazard spectrum for the design are considered. The performance of the building near the Chiplun fault in Mumbai, India shows operational under UHS-500 (uniform hazard spectrum) event and it collapses when the building is exposed to UHS-2500 record. The thesis is concluded in Chapter-6 with an overall summary of the report and suggestions for further scope of the work.
126

Functional Domain Motions and Processivity in Bacterial Hyaluronate Lyase / A Molecular Dynamics study / Functional Domain Motions and Processivity in Bacterial Hyaluronate Lyase / A Molecular Dynamics study

Joshi, Harshad 04 May 2007 (has links)
No description available.
127

Correlated and Further Dynamics in Proteins by NMR Spectroscopy / Korrelierte und weitere Dynamik in Proteinen mittels NMR Spektroskopie

Walter, Korvin 15 September 2011 (has links)
No description available.
128

Biomécanique de la locomotion humaine : influence de la chaussure et de la fatigue sur les ajustements neuro-mécaniques.

Morio, Cédric 09 December 2011 (has links)
Bien qu’il soit recommandé de pratiquer tout au long de sa vie une activité physique régulière pour se maintenir en bonne santé, peu d’études portent sur les modifications des patrons locomoteurs lors de la répétition de séances à 2 ou 3 jours d’intervalle. Lorsqu’elles sont intenses ou inhabituelles, les formes naturelles de locomotion pédestre – dites de type cycle étirement-détente (CED) – se caractérisent par des perturbations structuro-fonctionnelles et proprioceptives qui peuvent perdurer plusieurs jours. Ces déficiences sont autant de sources de risques accrus de blessures lors de la répétition d’une pratique sportive. Ce travail doctoral a pour objectif (i) d’examiner les effets immédiats et retardés d’exercices épuisants de type CED sur les paramètres neuromécaniques de la locomotion humaine en conditions de marche, de course et de sauts et (ii) d’étudier l’influence combinée d’une pratique pieds nus vs. pieds chaussés. Nos résultats ne révèlent pas de modification significative des patrons locomoteurs en phase de récupération immédiate (post-exercice) mais démontrent l’intervention de stratégies compensatrices et/ou protectrices en phase de récupération retardée (2ème jour posteffort). Ces stratégies diffèrent entre les conditions de marche et de course. Nos travaux soulignent également l’importance de discriminer les stratégies adoptées dès la première minute de l’exercice des ajustements ultérieurs apparaissant pendant la phase dite d’optimisation du CED. Par contre, les différences observées entre les conditions de course pieds nus vs. pieds chaussés restent étonnamment similaires avec la fatigue. Le port de chaussures se traduit par une réduction des chocs d’impact mais également par une restriction des mouvements naturels du pied et par une éversion accrue dont il conviendrait d’étudier les conséquences lors de la répétition en état de fatigue d’exercices de plus longue durée. / Although lifelong practice of moderate amounts of regular physical activity is recommended to ensure a healthy living state, little is know about the modifications of the locomotion patterns when repeating exercises every 2 to 3 days. Intense or unaccustomed stretch-shortening cycle (SSC) forms of ground locomotion are characterized, however, by structuro-functional and proprioceptive impairments that may last for a few days. These impairments may then be expected to increase the risk of injury. The present work aimed (i) to examine the acute and delayed SSC fatigue effects on the neuro-mechanical gait characteristics in walking, running and jumping conditions and (ii) to study the combined influence of a barefoot vs. shod gait condition. Our results did not reveal any modification of the locomotion patterns in the acute recovery phase (post-exercise), but demonstrated compensatory and/or protective strategies in the delayed phase (2 days post-exercise). The observed strategies differed significantly in walking and running. Our results emphasized also the need to differentiate the strategies occurring within the first minute of exercise from the subsequent adjustments related to the progressive SSC pattern optimization. Surprisingly, the observed differences between the barefoot and shod running conditions remained quite independent of the fatigue state. The shod running condition was thus found to attenuate ground impact transmission, but it resulted also in restricted natural foot motions and increased eversion that should be worth re-examining when repeating exercises of longer duration.
129

Propriedades recursivas em sistemas semidinâmicos impulsivos / Recursive properties in impulsive semidynamical systems

Manuel Francisco Zuloeta Jiménez 06 December 2013 (has links)
A teoria de sistemas semidinâmicos impulsivos é um capítulo importante e moderno da teoria de sistemas dinâmicos topológicos. Sistemas impulsivos descrevem processos de evolução que sofrem variações de estado de curta duração e que podem ser consideradas instantâneas. Os sistemas impulsivos admitem vários fenômenos interessantes às vezes, por causa da sua irregularidade, e às vezes por causa da sua regularidade. Para muitos fenômenos naturais, os modelos determinísticos mais realistas são frequentemente descritos por sistemas que envolvem impulsos. Esta teoria vem sendo desenvolvida continuamente. O presente trabalho apresenta resultados originais sobre a teoria de conjuntos minimais, movimentos recorrentes, movimentos quase periódicos e fracamente quase periódicos, teoria de estabilidade de Lyapunov, teoria da quase estabilidade de Zhukovskij e, finalmente, a construção de trajetórias negativas para sistemas semidinâmicos com impulsos. Os resultados novos apresentados neste trabalho estão contidos em três artigos, dos quais dois já foram aceitos para publicação. Veja [13], [14] e [15] / The theory of impulsive semidynamical systems is an important and modern chapter of the theory of topological dynamical systems. Impulsive systems describe the evolution of process whose continuous dynamics are interrupted by abrupt changes of state. This kind of systems admits various interesting phenomena sometimes, because of their irregularity, and sometimes because of their regularity. In many natural phenomena, the real deterministic models are often described by systems which involve impulses. This theory has been developed continuously. This work presents original results involving the theory of minimal sets, recurrent motions, almost periodic and weakly almost periodic motions, the study of Lyapunov stability and Zhukovshij Quasi stability and the construction of negative trajectories for impulsive semidynamical systems. The new results presented in this work are contained in three papers namely [13], [14] and [15]
130

Shock Wave-boundary Layer Interaction in Supersonic Flow over Compression Ramp and Forward-Facing Step

Jayaprakash Narayan, M January 2014 (has links) (PDF)
Shock wave-boundary layer interactions (SWBLIs) have been studied ex-tensively due to their practical importance in the design of high speed ve-hicles. These interactions, especially the ones leading to shock induced separation are typically unsteady in nature and can lead to large fluctuating pressure and thermal loads on the structure. The resulting shock oscil-lations are generally composed of high-frequency small-scale oscillations and low-frequency large-scale oscillations, the source of the later being a subject of intense recent debate. Motivated by these debates, we study in the present work, the SWBLI at a compression ramp and on a forward-facing step (FFS) at a Mach number of 2.5. In the case of compression ramps, a few ramp angles are studied ranging from small (10 degree) ramp angle to relatively large values of up to 28 degrees. The FFS configuration, which consists of a 90 degree step of height h, may be thought of as an extreme case of the compression ramp geometry, with the main geometri-cal parameter here being (h/δ), where δis the thickness of the oncoming boundary layer. This configuration is less studied and has some inherent advantages for experimentally studying SWBLI as the size of the separa-tion bubble is large. In the present experimental study, we use high-speed schlieren, unsteady wall pressure measurements, surface oil flow visualiza-tion, and detailed particle image velocimetry (PIV) measurements in two orthogonal planes to help understand the features of SWBLI in the com-pression ramp geometry and the forward-facing step case. The SWBLI at a compression ramp has been more widely studied, and our measurements show the general features that have been seen in earlier studies. The upstream boundary layer is found to separate close to the ramp corner forming a separation bubble. The streamwise length of the separa-tion bubble is found to increase with the ramp angle, with a consequent shift of the shock foot further upstream. At very small ramp angles up to 10 degrees, there is no evidence of separation, while at large ramp angles of 28 degrees, the separation bubble extends upstream to about 3.5δ(δ=boundary layer thickness). In all cases, the separation bubble is however very small in the wall normal direction, typically known to be about 0.1δ, and hence is difficult to directly measure in experiments using PIV. Shock foot measurements using PIV show that the shock has a spanwise ripple, which seems directly related to the high-and low-speed streaks in the in-coming boundary layer as recently shown by Ganapathisubramani et al. (2007). The forward-facing step configuration may be thought of as an extreme case of the compression ramp geometry, with a ramp angle of 90 degrees. This configuration has not been extensively studied, and is experimentally convenient due to the large separation bubbles formed ahead of the step. In the present work, extensive measurements of the mean and unsteady flow around this configuration have been done, especially for the case of h/δ=2, where his the step height. Pressure measurements in this case, show clear low-frequency motions of the shock at non-dimensional frequencies of about fh/U∞≈ 0.02. In this case, PIV measurements show the pres-ence of a large mean separation bubble extending to about 4hupstream and about 1hvertically. Instantaneous PIV measurements have been done in both cross-stream (streamwise and wall-normal plane) and in the span-wise (streamwise-spanwise) plane. Instantaneous cross-stream PIV mea-surements show significant variations of the shock location and angle, be-sides large variations in the recirculation region (or separation bubble), this being determined as the area having streamwise velocities less than zero. From a large set of individual PIV instantaneous fields, we can estimate the correlation of the measured shock location to both downstream effects like the area of the recirculation region, and upstream effects like the presence of high-/low-speed streaks in the oncoming boundary layer. We find that the shock location measured from data outside the boundary layer is more highly correlated to downstream effects as measured through the recircu-lation area compared to upstream effects in the boundary layer. However, we find that the shock foot within the boundary layer has ripples in the spanwise direction which are well correlated to the presence of high-/low-speed streaks in the incoming boundary layer. These spanwise ripples are however found to be small (less than one h) compared to the highly three-dimensional shape of the recirculation region with spanwise variation of the order of 3 step heights. In summary, the study shows that the separated region ahead of the step is highly three-dimensional. The shock foot within the boundary layer is found to have ripples that are well correlated to fluctuations in the in-coming boundary layer. However, we find that the large-scale nearly two-dimensional shock motions outside the boundary layer are not well cor-related to the fluctuations in the boundary layer, but are instead well cor-related with the spanwise-averaged separation bubble extent. Hence, the present results suggest that for the forward-facing step configuration, it is the downstream effect caused by the separation bubble that leads to the observed low-frequency shock motions.

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